Expander heads, driving devices and couplings of the aforementioned type are conventionally part of an expander device, by means of which pipes and hoses are expanded. For this purpose, an expanding mandrel is moved in a translational manner in the direction of an axis, by means of the driving device, resulting in the expanding mandrel acting on the expander head. The expander head conventionally comprises expanding jaws, the outer faces of which press against and expand the inner circumference of the pipe or hose which is to be expanded. For this purpose, the contact force of the expanding jaws is conventionally brought about by the expanding mandrel, which acts on control faces of the expanding jaws during the axial movement of said mandrel, in such a way that the actuation force which is produced by the driving device is transferred via the axial movement of the expanding mandrel into a movement of the expander jaws in the radial direction.
As a result of the coupling of the expander device, the expander head and the driving device are held releasably against one another.
It is necessary in practice for the expander head to be releasable from the driving device in this manner, since the expander device is used to expand pipes and hoses of different materials, having different expansion properties and different diameters. For this purpose, whole arsenals of expander heads are conventionally provided on building sites or in manufacturing operations. It is thus necessary to change the expander heads frequently in practice.
One option for fixing the expander head to the driving device of the expander device is known from DE 10 2007 007 294 B3. In this case, the expander head and the driving device are interconnected by means of a screw coupling. For this purpose, the expander head comprises an internal thread, which can be screwed onto an external thread of the driving device for fixing to the driving device. Nowadays, screw couplings of this type are widespread in expander devices.